juce_Displays.cpp

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/*
  ==============================================================================
 
   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited
 
   JUCE is an open source library subject to commercial or open-source
   licensing.
 
   By using JUCE, you agree to the terms of both the JUCE 7 End-User License
   Agreement and JUCE Privacy Policy.
 
   End User License Agreement: www.juce.com/juce-7-licence
   Privacy Policy: www.juce.com/juce-privacy-policy
 
   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).
 
   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.
 
  ==============================================================================
*/
 
namespace juce
{
 
Displays::Displays (Desktop& desktop)
{
    init (desktop);
}
 
void Displays::init (Desktop& desktop)
{
    findDisplays (desktop.getGlobalScaleFactor());
}
 
const Displays::Display* Displays::getDisplayForRect (Rectangle<int> rect, bool isPhysical) const noexcept
{
    int maxArea = -1;
    const Display* foundDisplay = nullptr;
 
    for (auto& display : displays)
    {
        auto displayArea = display.totalArea;
 
        if (isPhysical)
            displayArea = (displayArea.withZeroOrigin() * display.scale) + display.topLeftPhysical;
 
        displayArea = displayArea.getIntersection (rect);
        auto area = displayArea.getWidth() * displayArea.getHeight();
 
        if (area >= maxArea)
        {
            maxArea = area;
            foundDisplay = &display;
        }
    }
 
    return foundDisplay;
}
 
const Displays::Display* Displays::getDisplayForPoint (Point<int> point, bool isPhysical) const noexcept
{
    auto minDistance = std::numeric_limits<int>::max();
    const Display* foundDisplay = nullptr;
 
    for (auto& display : displays)
    {
        auto displayArea = display.totalArea;
 
        if (isPhysical)
            displayArea = (displayArea.withZeroOrigin() * display.scale) + display.topLeftPhysical;
 
        if (displayArea.contains (point))
            return &display;
 
        auto distance = displayArea.getCentre().getDistanceFrom (point);
 
        if (distance <= minDistance)
        {
            minDistance = distance;
            foundDisplay = &display;
        }
    }
 
    return foundDisplay;
}
 
Rectangle<int> Displays::physicalToLogical (Rectangle<int> rect, const Display* useScaleFactorOfDisplay) const noexcept
{
    return physicalToLogical (rect.toFloat(), useScaleFactorOfDisplay).toNearestInt();
}
 
Rectangle<float> Displays::physicalToLogical (Rectangle<float> rect, const Display* useScaleFactorOfDisplay) const noexcept
{
    const auto* display = useScaleFactorOfDisplay != nullptr ? useScaleFactorOfDisplay
                                                             : getDisplayForRect (rect.toNearestInt(), true);
 
    if (display == nullptr)
        return rect;
 
    auto globalScale = Desktop::getInstance().getGlobalScaleFactor();
 
    return ((rect - display->topLeftPhysical.toFloat()) / (display->scale / globalScale))
            + (display->totalArea.getTopLeft().toFloat() * globalScale);
}
 
Rectangle<int> Displays::logicalToPhysical (Rectangle<int> rect, const Display* useScaleFactorOfDisplay) const noexcept
{
    return logicalToPhysical (rect.toFloat(), useScaleFactorOfDisplay).toNearestInt();
}
 
Rectangle<float> Displays::logicalToPhysical (Rectangle<float> rect, const Display* useScaleFactorOfDisplay) const noexcept
{
    const auto* display = useScaleFactorOfDisplay != nullptr ? useScaleFactorOfDisplay
                                                             : getDisplayForRect (rect.toNearestInt(), false);
 
    if (display == nullptr)
        return rect;
 
    auto globalScale = Desktop::getInstance().getGlobalScaleFactor();
 
    return ((rect.toFloat() - (display->totalArea.getTopLeft().toFloat() * globalScale)) * (display->scale / globalScale))
             + display->topLeftPhysical.toFloat();
}
 
template <typename ValueType>
Point<ValueType> Displays::physicalToLogical (Point<ValueType> point, const Display* useScaleFactorOfDisplay) const noexcept
{
    const auto* display = useScaleFactorOfDisplay != nullptr ? useScaleFactorOfDisplay
                                                             : getDisplayForPoint (point.roundToInt(), true);
 
    if (display == nullptr)
        return point;
 
    auto globalScale = Desktop::getInstance().getGlobalScaleFactor();
 
    Point<ValueType> logicalTopLeft  (static_cast<ValueType> (display->totalArea.getX()),       static_cast<ValueType> (display->totalArea.getY()));
    Point<ValueType> physicalTopLeft (static_cast<ValueType> (display->topLeftPhysical.getX()), static_cast<ValueType> (display->topLeftPhysical.getY()));
 
    return ((point - physicalTopLeft) / (display->scale / globalScale)) + (logicalTopLeft * globalScale);
}
 
template <typename ValueType>
Point<ValueType> Displays::logicalToPhysical (Point<ValueType> point, const Display* useScaleFactorOfDisplay)  const noexcept
{
    const auto* display = useScaleFactorOfDisplay != nullptr ? useScaleFactorOfDisplay
                                                             : getDisplayForPoint (point.roundToInt(), false);
 
    if (display == nullptr)
        return point;
 
    auto globalScale = Desktop::getInstance().getGlobalScaleFactor();
 
    Point<ValueType> logicalTopLeft  (static_cast<ValueType> (display->totalArea.getX()),       static_cast<ValueType> (display->totalArea.getY()));
    Point<ValueType> physicalTopLeft (static_cast<ValueType> (display->topLeftPhysical.getX()), static_cast<ValueType> (display->topLeftPhysical.getY()));
 
    return ((point - (logicalTopLeft * globalScale)) * (display->scale / globalScale)) + physicalTopLeft;
}
 
const Displays::Display* Displays::getPrimaryDisplay() const noexcept
{
    JUCE_ASSERT_MESSAGE_MANAGER_IS_LOCKED
 
    for (auto& d : displays)
        if (d.isMain)
            return &d;
 
    return nullptr;
}
 
RectangleList<int> Displays::getRectangleList (bool userAreasOnly) const
{
    JUCE_ASSERT_MESSAGE_MANAGER_IS_LOCKED
    RectangleList<int> rl;
 
    for (auto& d : displays)
        rl.addWithoutMerging (userAreasOnly ? d.userArea : d.totalArea);
 
    return rl;
}
 
Rectangle<int> Displays::getTotalBounds (bool userAreasOnly) const
{
    return getRectangleList (userAreasOnly).getBounds();
}
 
void Displays::refresh()
{
    Array<Display> oldDisplays;
    oldDisplays.swapWith (displays);
 
    init (Desktop::getInstance());
 
    if (oldDisplays != displays)
    {
        for (auto i = ComponentPeer::getNumPeers(); --i >= 0;)
            if (auto* peer = ComponentPeer::getPeer (i))
                peer->handleScreenSizeChange();
    }
}
 
bool operator== (const Displays::Display& d1, const Displays::Display& d2) noexcept;
bool operator== (const Displays::Display& d1, const Displays::Display& d2) noexcept
{
    return d1.isMain          == d2.isMain
        && d1.totalArea       == d2.totalArea
        && d1.userArea        == d2.userArea
        && d1.topLeftPhysical == d2.topLeftPhysical
        && d1.scale           == d2.scale
        && d1.dpi             == d2.dpi;
}
 
bool operator!= (const Displays::Display& d1, const Displays::Display& d2) noexcept;
bool operator!= (const Displays::Display& d1, const Displays::Display& d2) noexcept    { return ! (d1 == d2); }
 
//==============================================================================
// These methods are used for converting the totalArea and userArea Rectangles in Display from physical to logical
// pixels. We do this by constructing a graph of connected displays where the root node has position (0, 0); this can be
// safely converted to logical pixels using its scale factor and we can then traverse the graph and work out the logical pixels
// for all the other connected displays. We need to do this as the logical bounds of a display depend not only on its scale
// factor but also the scale factor of the displays connected to it.

struct DisplayNode
{
    Displays::Display* display;

    bool isRoot = false;

    DisplayNode* parent = nullptr;

    Rectangle<double> logicalArea;
};

static void processDisplay (DisplayNode* currentNode, Array<DisplayNode>& allNodes)
{
    const auto physicalArea = currentNode->display->totalArea.toDouble();
    const auto scale = currentNode->display->scale;
 
    if (! currentNode->isRoot)
    {
        const auto logicalWidth  = physicalArea.getWidth() / scale;
        const auto logicalHeight = physicalArea.getHeight() / scale;
 
        const auto physicalParentArea = currentNode->parent->display->totalArea.toDouble();
        const auto logicalParentArea  = currentNode->parent->logicalArea; // logical area of parent has already been calculated
        const auto parentScale        = currentNode->parent->display->scale;
 
        Rectangle<double> logicalArea (0.0, 0.0, logicalWidth, logicalHeight);
 
        if      (physicalArea.getRight() == physicalParentArea.getX())     logicalArea.setPosition ({ logicalParentArea.getX() - logicalWidth, physicalArea.getY() / parentScale });  // on left
        else if (physicalArea.getX() == physicalParentArea.getRight())     logicalArea.setPosition ({ logicalParentArea.getRight(),  physicalArea.getY() / parentScale });            // on right
        else if (physicalArea.getBottom() == physicalParentArea.getY())    logicalArea.setPosition ({ physicalArea.getX() / parentScale, logicalParentArea.getY() - logicalHeight }); // on top
        else if (physicalArea.getY() == physicalParentArea.getBottom())    logicalArea.setPosition ({ physicalArea.getX() / parentScale, logicalParentArea.getBottom() });            // on bottom
        else                                                               jassertfalse;
 
        currentNode->logicalArea = logicalArea;
    }
    else
    {
        // If currentNode is the root (position (0, 0)) then we can just scale the physical area
        currentNode->logicalArea = physicalArea / scale;
        currentNode->parent = currentNode;
    }
 
    // Find child nodes
    Array<DisplayNode*> children;
    for (auto& node : allNodes)
    {
        // Already calculated
        if (node.parent != nullptr)
            continue;
 
        const auto otherPhysicalArea = node.display->totalArea.toDouble();
 
        // If the displays are touching on any side
        if (otherPhysicalArea.getX() == physicalArea.getRight()  || otherPhysicalArea.getRight() == physicalArea.getX()
            || otherPhysicalArea.getY() == physicalArea.getBottom() || otherPhysicalArea.getBottom() == physicalArea.getY())
        {
            node.parent = currentNode;
            children.add (&node);
        }
    }
 
    // Recursively process all child nodes
    for (auto child : children)
        processDisplay (child, allNodes);
}

void Displays::updateToLogical()
{
    if (displays.size() == 1)
    {
        auto& display = displays.getReference (0);
 
        display.totalArea = (display.totalArea.toDouble() / display.scale).toNearestInt();
        display.userArea  = (display.userArea.toDouble()  / display.scale).toNearestInt();
 
        return;
    }
 
    Array<DisplayNode> displayNodes;
 
    for (auto& d : displays)
    {
        DisplayNode node;
 
        node.display = &d;
 
        if (d.totalArea.getTopLeft() == Point<int>())
            node.isRoot = true;
 
        displayNodes.add (node);
    }
 
    auto* root = [&displayNodes]() -> DisplayNode*
    {
        for (auto& node : displayNodes)
            if (node.isRoot)
                return &node;
 
        auto minDistance = std::numeric_limits<int>::max();
        DisplayNode* retVal = nullptr;
 
        for (auto& node : displayNodes)
        {
            auto distance = node.display->totalArea.getTopLeft().getDistanceFrom ({});
 
            if (distance < minDistance)
            {
                minDistance = distance;
                retVal = &node;
            }
        }
 
        if (retVal != nullptr)
            retVal->isRoot = true;
 
        return retVal;
    }();
 
    // Must have a root node!
    jassert (root != nullptr);
 
    // Recursively traverse the display graph from the root and work out logical bounds
    processDisplay (root, displayNodes);
 
    for (auto& node : displayNodes)
    {
        // All of the nodes should have a parent
        jassert (node.parent != nullptr);
 
        auto relativeUserArea = (node.display->userArea.toDouble() - node.display->totalArea.toDouble().getTopLeft()) / node.display->scale;
 
        // Now set Display::totalArea and ::userArea using the logical area that we have calculated
        node.display->topLeftPhysical = node.display->totalArea.getTopLeft();
        node.display->totalArea       = node.logicalArea.toNearestInt();
        node.display->userArea        = (relativeUserArea + node.logicalArea.getTopLeft()).toNearestInt();
    }
}
 
#ifndef DOXYGEN
 // explicit template instantiations
 template Point<int>   Displays::physicalToLogical (Point<int>,   const Display*) const noexcept;
 template Point<float> Displays::physicalToLogical (Point<float>, const Display*) const noexcept;
 
 template Point<int>   Displays::logicalToPhysical (Point<int>,   const Display*) const noexcept;
 template Point<float> Displays::logicalToPhysical (Point<float>, const Display*) const noexcept;
#endif
 
//==============================================================================
// Deprecated methods
const Displays::Display& Displays::getDisplayContaining (Point<int> position) const noexcept
{
    JUCE_ASSERT_MESSAGE_MANAGER_IS_LOCKED
    const auto* best = &displays.getReference (0);
    auto bestDistance = std::numeric_limits<int>::max();
 
    for (auto& d : displays)
    {
        if (d.totalArea.contains (position))
        {
            best = &d;
            break;
        }
 
        auto distance = d.totalArea.getCentre().getDistanceFrom (position);
 
        if (distance < bestDistance)
        {
            bestDistance = distance;
            best = &d;
        }
    }
 
    return *best;
}
 
const Displays::Display& Displays::findDisplayForRect (Rectangle<int> rect, bool isPhysical) const noexcept
{
    if (auto* display = getDisplayForRect (rect, isPhysical))
        return *display;
 
    return emptyDisplay;
}
 
const Displays::Display& Displays::findDisplayForPoint (Point<int> point, bool isPhysical) const noexcept
{
    if (auto* display = getDisplayForPoint (point, isPhysical))
        return *display;
 
    return emptyDisplay;
}
 
const Displays::Display& Displays::getMainDisplay() const noexcept
{
    if (auto* display = getPrimaryDisplay())
        return *display;
 
    return emptyDisplay;
}
 
} // namespace juce